TRPV1 and obesity due to melanocortin 4 receptor deficiency: To explore the role of TRPV1-positive afferent renal nerves in obesity-related renal injury, we chronically and specifically activate TRPV1 channels in afferent renal nerves with an intrathecal N-oleoyldopamine (OLDA, an endogenous TRPV1 agonist) injection in the present study.